South Pacific tropical cyclone

Last updated May 10, 2020

A South Pacific tropical cyclone is a non frontal, low pressure system that has developed, within an environment of warm sea surface temperatures and little vertical wind shear aloft in the South Pacific Ocean.[1] Within the Southern Hemisphere there are officially three areas where tropical cyclones develop on a regular basis, these areas are the South-West Indian Ocean between Africa and 90°E, the Australian region between 90°E and 160°E and the South Pacific basin between 160°E and 120°W. The South Pacific basin between 160°E and 120°W is officially monitored by the Fiji Meteorological Service and New Zealand's MetService, while others like the Australian Bureau of Meteorology and the United States National Oceanic and Atmospheric Administration also monitor the basin. Each tropical cyclone year within this basin starts on July 1 and runs throughout the year, encompassing the tropical cyclone season which runs from November 1 and lasts until April 30 each season. Within the basin, most tropical cyclones have their origins within the South Pacific Convergence Zone or within the Northern Australian monsoon trough, both of which form an extensive area of cloudiness and are dominant features of the season. Within this region a tropical disturbance is classified as a tropical cyclone, when it has 10-minute sustained wind speeds of more than 65km/h (35mph), that wrap halfway around the low level circulation centre, while a severe tropical cyclone is classified when the maximum 10-minute sustained wind speeds are greater than 120km/h (75mph).

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Basin history

The ancient mariners of the South Seas who roamed the tropical Pacific before the arrival of the Europeans, knew of and feared the hurricanes of the South Pacific.[2] They were keen and accurate observers of nature with traditional myths and legends, reflecting their knowledge of these systems.[2] On his voyages around the Pacific, it is thought that Captain James Cook did not collect any information about cyclones in the Pacific.[2] The European whalers, traders and missionaries that followed Cook soon realised that the South Pacific was not free of hurricanes, and were the first to publish accounts about the systems.[2] During 1853, Thomas Dobson subsequently became the first person to collect information about these systems, in order to attempt to understand and explain the characteristics of 24 tropical cyclones.[2] However, these descriptions were vague and of little value, because he only had a small amount of data and no synoptic weather charts.[2]

Over the next 40 years various reports, journals and log books on the storms were published, before E. Knipping consolidated these reports and extended Dobson's list out to 120 tropical cyclones during 1893.[2] During the 1920s Stephen Sargent Visher did some research into tropical cyclones in the Pacific and visited several island nations; including Fiji, Japan and the Philippines to obtain information on potential systems.[3] He also consulted various journals and reports as well as Dobson's and Knipping's work, before he authored a number of papers on tropical cyclones in the Pacific.[3] These papers contained information about 259 tropical storms in the South Pacific between 160°E and 140°W, two of which occurred during 1789 and 1819, while the rest occurred between 1830 and 1923.[2] Visher also tried to estimate how many systems were occurring on an annual basis in each area, but overcompensated for his incomplete records and came up with a figure of 12 severe tropical cyclones per year.[2][3]

During Visher's time and until the start of World War Two, there was insufficient information available to allow for an accurate depiction of tropical cyclone tracks.[2] However, in the buildup to and during World War Two, meteorological operations in the Pacific were greatly expanded, to meet the needs of international aviation and military operations.[2][4] As a result, J W Hutchings decided to write a paper on 43 tropical cyclones between 1940 and 1951, using data that had been collected from the tropics by the New Zealand Meteorological Service in the area between the 150°E and 150°W.[4] In the paper, systems were only included if they had a wind speed on the Beaufort scale of Force 9 or above, while located between the Equator and 30°S.[4] Hutchings also examined where tropical cyclones originated from in the South Pacific and claimed that the place where most tropical cyclones develop could be accurately determined.[2][4] The paper also drew attention to a marked difference in the tracks of South Pacific tropical cyclones and systems in other basins.[4] This work was subsequently extended in 1956, by the then director of the New Zealand Meteorological Service: John Fletcher Gabites, to cover the seasons between 1952–53 and 1955–56.[5] Gabites subsequently wrote a series of papers during 1963 on various aspects of South Pacific tropical cyclones including on the wide variety of tracks that occur over the Pacific.[2]

During June 1995, the Fiji Meteorological Service's Nadi— Tropical Cyclone Centre, was designated as a Regional Specialized Meteorological Center by the World Meteorological Organization.

1980s

During the 1980s there were three major Southern Oscillation episodes; two El Niño's (1982–83 and 1986/87) when the Southern Oscillation Index (SOI) was negative and one La Nina when the SOI was positive.[14]

2000s

During the 2000s, activity was generally below the long term average, with 60 tropical cyclones developing out of 160 tropical disturbances and tropical depressions. However activity during the 2002–03, 2004–05 and 2009–10 seasons all experienced activity, near the long term average of about 8- 9 tropical cyclones.

↑ Number of tropical cyclones excludes Tropical Cyclone Anthony, which was considered to have weakened into a tropical low before moving into the South Pacific basin by the Australian Bureau of Meteorology during post analysis.[32][33]

↑ Number of tropical disturbances excludes Tropical Cyclone Raquel, which was considered by the Australian Bureau of Meteorology to be a Category 1 tropical cyclone within the 2014–15 year.[32][38]

Related Research Articles

The 2007–08 South Pacific cyclone season was one of the least active South Pacific tropical cyclone season's on record, with only four tropical cyclones occurring within the South Pacific basin to the east of 160°E. The season officially ran from November 1, 2007 until April 30, 2008, although the first cyclone, Tropical Depression 01F, developed on October 17. The most intense tropical cyclone of the season was Severe Tropical Cyclone Daman, which reached a minimum pressure of 925 hPa (27.32 inHg) as it affected Fiji. After the season had ended, the names Daman, Funa, and Gene were retired from the tropical cyclone naming lists.

The 2006–07 South Pacific cyclone season was an event in the annual cycle of tropical cyclone formation. It began on November 1, 2006 and ended on April 30, 2007. These dates conventionally delimit the period of each year when most tropical cyclones form in the southern Pacific Ocean east of 160°E. Additionally, the regional tropical cyclone operational plan defines a tropical cyclone year separately from a tropical cyclone season, and the "tropical cyclone year" runs from July 1, 2006 to June 30, 2007.

The 2004–05 South Pacific cyclone season was an above-average tropical cyclone season, that contained nineteen tropical disturbances and nine tropical cyclones. The season got off to an early start, when Tropical Depression 01F developed near the Solomon Islands on October 28, three days before the official start of the season on November 1. The final disturbance of the season dissipated as the season was drawing to a close on May 1, 2005. Tropical cyclones between 160°E and 120°W and north of 25°S are monitored by the Fiji Meteorological Service in Nadi. Those that move south of 25°S are monitored by the Tropical Cyclone Warning Centre in Wellington, New Zealand.

The 2003–04 South Pacific cyclone season was a below-average season with only three tropical cyclones occurring within the South Pacific to the east of 160°E. The season officially ran from November 1, 2003 to April 30, 2004 with the first disturbance of the season forming on December 4 and the last disturbance dissipating on April 23. This is the period of the year when most tropical cyclones form within the South Pacific Ocean.

The 2002–03 South Pacific cyclone season was the most active and longest tropical cyclone season since 1997–98, with ten tropical cyclones occurring within the South Pacific basin between 160°E and 120°W. The season started earlier than normal, with two systems developing before the official start of the season on November 1, 2002, while the final system dissipated on June 9, 2003, after the season had officially ended on April 30. During the season, tropical cyclones were officially monitored by the Regional Specialized Meteorological Centre (RSMC) in Nadi, Fiji and the Tropical Cyclone Warning Centres in Brisbane, Australia and Wellington, New Zealand. The United States Armed Forces through the Joint Typhoon Warning Center (JTWC), also monitored the basin and issued unofficial warnings for American interests. RSMC Nadi attaches a number and an F suffix to tropical disturbances that occur within the basin, while the JTWC designates significant tropical cyclones with a number and a P suffix. RSMC Nadi, TCWC Wellington and TCWC Brisbane all use the Australian Tropical Cyclone Intensity Scale and estimate windspeeds over a ten-minute period, while the JTWC estimates sustained winds over a one-minute period, which are subsequently compared to the Saffir–Simpson Hurricane Scale (SSHS).

The 2008–09 South Pacific cyclone season was a below average tropical cyclone season, which featured six named tropical cyclones compared to an average of about nine. Ahead of the season officially starting on November 1, 2008, the Island Climate Update tropical cyclone outlook predicted that the season, would feature an average risk of tropical cyclones impacting the South Pacific between 160°E and 120°W. The first tropical disturbance of the season developed to the northeast of the Samoan Islands on December 1, however, it remained weak and was last noted during the next day.

Severe Tropical Cyclone Gene was the deadliest storm as well as the most damaging tropical cyclone of the 2007–08 South Pacific cyclone season east of 160ºE. RSMC Nadi monitored Gene as the 12th tropical disturbance, as well as the fourth tropical cyclone and the third severe tropical cyclone to form west of 160ºE during the 2007–08 South Pacific cyclone season. Gene was also recognised by RSMC Nadi as the fifth tropical cyclone and fourth severe tropical cyclone to form within the South Pacific Ocean during the 2007-08 season.

The 2009–10 South Pacific cyclone season began on December 3, 2009 with the formation of Tropical Disturbance 01F, 32 days after the cyclone season had officially begun on November 1, 2009. The season ended on April 30, 2010. These dates conventionally delimit the period of each year when most tropical cyclones form in the southern Pacific Ocean east of 160°E. Additionally, the regional tropical cyclone operational plan defines a tropical cyclone year separately from a tropical cyclone season; the "tropical cyclone year" began on July 1, 2009 and ended on June 30, 2010. Tropical cyclones between 160°E and 120°W and north of 25°S are monitored by the Fiji Meteorological Service. Those that move south of 25°S are monitored by the Tropical Cyclone Warning Centre in Wellington, New Zealand. The first tropical disturbance of the season formed on December 3, about 1015 km (700 mi) to the north of Suva, Fiji and later intensified into Tropical Cyclone Mick. The last system, 15F, dissipated on April 5 of the following year.

The 1996–97 South Pacific cyclone season was one of the most active and longest South Pacific tropical cyclone seasons on record, with 12 tropical cyclones occurring within the South Pacific basin between 160°E and 120°W. The season officially ran from November 1, 1996 - April 30, 1997, however, the season ended later than normal with three systems monitored after the official end of the season. The strongest tropical cyclone of the season was Cyclone Gavin which had a minimum pressure of 925 hPa (27.32 inHg). After the season had ended 4 tropical cyclone names were retired from the naming lists, after the cyclones had caused significant impacts to South Pacific islands.

The 2010–11 South Pacific cyclone season was an average tropical cyclone season, with seven tropical cyclones and five severe tropical cyclones developing during the season. The season ran from November 1, 2010 until April 30, 2011, though if any tropical cyclones had developed between July 1, 2010 and June 30, 2011, the official tropical cyclone year, they would have been counted towards the season's total. Within the South Pacific basin tropical cyclones were officially monitored by the Fiji Meteorological Service's Regional Specialized Meteorological Center in Nadi, Fiji, north of 25°S, and to the south the Meteorological Service of New Zealand's Tropical Cyclone Warning Center in Wellington, New Zealand. Any disturbances forming in the region were designated with a sequential number suffixed by the letter F. In addition, the United States Military's Joint Typhoon Warning Center unofficially monitored parts of the basin during the season, where any systems judged to have achieved tropical storm strength or greater received a number suffixed with the letter P. RSMC Nadi and TCWC Wellington both use the Australian Tropical Cyclone Intensity Scale, and measure wind speeds over a period of ten minutes, while the JTWC measures sustained winds over a period of one minute which can be applied to the Saffir–Simpson Hurricane Scale. Seven named storms formed or moved into the South Pacific basin during the 2010–11 season, the strongest of which was Severe Tropical Cyclone Wilma in late January.

The 2011–12 South Pacific cyclone season was one of the least active South Pacific tropical cyclone seasons on record, with only three tropical cyclones occurring during the season. The season ran from November 1, 2011 to April 30, 2012, however, any tropical cyclones that form before June 30, 2012 would have fallen within the 2011–12 tropical cyclone year and would have counted towards the season total. The strongest and only severe tropical cyclone that occurred during the season was Severe Tropical Cyclone Jasmine, which tracked in from out of the South Pacific basin. Within the basin, tropical cyclones are monitored by the Regional Specialized Meteorological Center (RSMC) in Nadi, Fiji, and the Tropical Cyclone Warning Center (TCWC) in Wellington, New Zealand. RSMC Nadi attaches an F designation to tropical disturbances that form in or move into the South Pacific. The United States Joint Typhoon Warning Center (JTWC) issues unofficial warnings within the South Pacific, designating tropical storm-equivalent or greater tropical cyclones with a number and a P suffix. RSMC Nadi and TCWC Wellington both use the Australian Tropical Cyclone Intensity Scale, and measure windspeeds over a period of ten minutes, while the JTWC measures sustained winds over a period of one minute and uses the Saffir–Simpson Hurricane Scale.

The 2012–13 South Pacific cyclone season was a somewhat below average tropical cyclone season, with six tropical cyclones occurring within the basin between 160°E and 120°W. The season officially ran from November 1, 2012 to April 30, 2013, however the last tropical disturbance was last noted on May 1, as it moved into the subtropics. During the season, tropical cyclones were officially monitored by the Fiji Meteorological Service (FMS), Australian Bureau of Meteorology (BoM) and New Zealand's MetService. The United States Joint Typhoon Warning Center (JTWC) and other national meteorological services including Météo-France and NOAA also monitored the basin during the season. During the season there were 22 significant tropical disturbances assigned a number and a F suffix by the FMS's Regional Specialized Meteorological Center in Nadi, Fiji (RSMC Nadi), including Severe Tropical Cyclone Sandra which moved into the basin from the Australian region on March 9. The BoM, MetService and RSMC Nadi all estimated sustained wind speeds over a period of 10-minutes and used the Australian tropical cyclone intensity scale, while the JTWC estimated sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHS).

The 1995–96 South Pacific cyclone season was one of the least active South Pacific tropical cyclone season's on record, with only four tropical cyclones occurring within the South Pacific Ocean to the east of 160°E. The season officially ran from November 1, 1995, until April 30, 1996. The first storm developed on January 12, while the last one dissipated on April 2. During the season the most intense tropical cyclone was Severe Tropical Cyclone Beti, which reached a minimum pressure of 935 hPa (27.61 inHg) as it affected New Caledonia. After the season ended Beti's name was the only name to be retired from the tropical cyclone naming lists and was replaced with Bune, after it inflicted over 5.6 million (USD) worth of damage to Australia, Vanuatu, New Caledonia and New Zealand.

The 2013–14 South Pacific cyclone season was a slightly below average tropical cyclone season, with six tropical cyclones occurring within the basin between 160°E and 120°W. The season ran from November 1, 2013 to April 30, 2014, however, the first four tropical disturbances occurred during October 2013 and were included as a part of the season. During the season, tropical cyclones were officially monitored by the Fiji Meteorological Service (FMS), Australian Bureau of Meteorology (BoM) and New Zealand's MetService. The United States Joint Typhoon Warning Center (JTWC) and other national meteorological services including Météo-France and NOAA also monitored the basin during the season. During the season there were 21 significant tropical disturbances were assigned a number and an "F" suffix by the FMS's Regional Specialized Meteorological Center in Nadi, Fiji (RSMC Nadi), including the remnants of Tropical Cyclone Hadi from the Australian region. The BoM, MetService and RSMC Nadi all estimated sustained wind speeds over a period of 10-minutes and used the Australian tropical cyclone intensity scale, while the JTWC estimated sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHS).

The 2014–15 South Pacific cyclone season was a slightly-below average tropical cyclone season, with five tropical cyclones occurring within the basin between 160°E and 120°W. The season officially ran from November 1, 2014 to April 30, 2015. During the season, tropical cyclones were officially monitored by the Regional Specialized Meteorological Center (RSMC) in Nadi, Fiji and the Tropical Cyclone Warning Centers in Brisbane, Australia and Wellington, New Zealand. The United States Armed Forces through the Joint Typhoon Warning Center (JTWC) also monitored the basin and issued unofficial warnings for American interests. RSMC Nadi attaches a number and an F suffix to tropical disturbances that form in or move into the basin while the JTWC designates significant tropical cyclones with a number and a P suffix. RSMC Nadi, TCWC Wellington and TCWC Brisbane all use the Australian Tropical Cyclone Intensity Scale and estimate windspeeds over a period of ten minutes, while the JTWC estimated sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHWS).

The 2015–16 South Pacific cyclone season was one of the most disastrous South Pacific tropical cyclone seasons on record, with a total of 50 deaths and $1.405 billion in damage. Throughout the season, 8 systems attained tropical cyclone status, whilst 5 became severe tropical cyclones. The most notable cyclone of the season by far was Winston, which attained a minimum pressure of 884 hPa, and maximum ten-minute sustained winds of 175 mph (280 km/h), making it the most intense tropical cyclone on record in the Southern Hemisphere. Winston went on to devastate Fiji, causing $1.4 billion in damage and 44 deaths across the country.

The 2016–17 South Pacific cyclone season was the least active South Pacific cyclone season since the 2011–12 season, with only four tropical cyclones occurring within the South Pacific Ocean to the east of 160°E. Two of the four systems developed into severe tropical cyclones on the Australian tropical cyclone intensity scale. The season officially ran from November 1, 2016 until April 30, 2017. However, May featured two post-season systems: Donna and Ella, of which the former was the strongest post-season South Pacific tropical cyclone ever recorded in that month. Overall, 22 tropical disturbances were monitored by a combination of the Fiji Meteorological Service (FMS), Australian Bureau of Meteorology (BoM) and New Zealand's MetService.

The 2017–18 South Pacific cyclone season was a slightly below-average season that produced 6 tropical cyclones, 3 of which became severe tropical cyclones. The season officially began on November 1, 2017 and ended on April 30, 2018; however, a tropical cyclone could form at any time between July 1, 2017 and June 30, 2018 and would count towards the season total. During the season, tropical cyclones were officially monitored by the Fiji Meteorological Service, MetService and the Australian Bureau of Meteorology, while the United States Joint Typhoon Warning Center (JTWC) also monitored the basin and issued warnings for American interests. The FMS attaches a number and an F suffix to significant tropical disturbances that form in or move into the basin, while the JTWC designates significant tropical cyclones with a number and a P suffix. The BoM, FMS and MetService all use the Australian Tropical Cyclone Intensity Scale and estimate wind speeds over a period of ten minutes, while the JTWC estimates sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHWS).

The 2018–19 South Pacific cyclone season was a below-average season that produced 5 tropical cyclones, 2 of which became severe tropical cyclones. The season officially runs from November 1, 2018 to April 30, 2019; however, a tropical cyclone could form at any time between July 1, 2018 and June 30, 2019 and would count towards the season total. During the season, tropical cyclones will be officially monitored by the Fiji Meteorological Service, Australian Bureau of Meteorology, and New Zealand's MetService. The United States Armed Forces through the Joint Typhoon Warning Center (JTWC) also monitored the basin and issued warnings for American interests. RSMC Nadi attaches a number and an F suffix to tropical disturbances that form in or move into the basin, while the JTWC designates significant tropical cyclones with a number and a P suffix. The FMS, the BoM and MetService all use the Australian Tropical Cyclone Intensity Scale and estimate wind speeds over a period of ten minutes, while the JTWC estimates sustained winds over a 1-minute period, which are subsequently compared to the Saffir–Simpson hurricane wind scale (SSHWS).

Cyclone Lusi was the second severe tropical cyclone of the 2013–14 season and affected Fiji, Vanuatu and New Zealand.